Where to put those engineers, though? In 2010, Facebook picked up a couple of floors in a building right on Madison Avenue—prime real estate to signal its ambitions to become an advertising player.

A source told us at the time that Facebook had snagged an option to expand to 150,000 feet at 335 Madison—enough for roughly 600 employees. That seems like plenty of space for both Facebook's New York sales team and an engineering office.

Aside from the prestigious address, though, that office isn't much to look at, and the location—Midtown East—is hardly a draw for the young, hip engineers Facebook wants to staff up with.

Times Square isn't much cooler, locationwise, but as Crain's notes, the owners have added amenities like a basketball court and AstroTurf. There's a real-estate arms race going on in New York to provide the most exciting workspaces, and Facebook knows it has to keep up.

There's also the symbolism of snagging the former home of the New York Times. Instead of kowtowing to Madison Avenue, Facebook could signal its ambitions to build a modern media company—the newspaper of tomorrow.

Or, you know, it just really wants a place for its engineers to shoot hoops.